Remote-control system for railway signals



July 2%, 194-7. J 2,424,696

REMOTE CONTROL SYSTEM FOR RAILWAY SIGNALS Filed July 29, 1944 2 Sheets-Sheet l a I FIGoiAc Faaozo July 29, 1947. JUDGE J I 2,424,696

REMO'JEE CONTROL SYSTEM FOR RAILWAY SIGNALS Filed July 29, 1944 2 Sheets-Sheet 2 J g. EH WM (Ittorneg Patented July 29,1947

REMOTE-CONTROL SYSTEM FOR RAILWAY SIGNALS.

Thomas J. Judge, Rochester, N. Y., assignor to General Railway N. Y.

Signal Company, Rochester,

Application July 29, 1944, Serial No. 547,176

1 This invention relates to communication systems for the remote selective control of the various lamps or indicators of route signals, yard track signals, and the like commonly used on railroads.

In connection with handling traflic into the various side tracks for storage yards, freight switching yards and the like, it is desirable to selectively control from a distant yard office or similar control point the indicating lamps or like indicators of a yard signal located at a convenient point with respect to the entrance to. the yard, so that the engineer of a train approaching the yard may be instructed where to put his train. This is a, typical application of a multiple aspect signal remotely controlled from a distant control point in accordance'with. this invention, but the same functions and mode of operation may be utilized for the control of route signals and the like. I

The primary object of this invention is'to provide a simple and effective organization for the selected remote control of yard signals over a minimum number of line wires and with a small number of relays of the conventional type.

Another object of the invention is to simplify the manipulation of a system of this character, and facilitate its use by office personnel in a yard office without special training. Various other objects, attributes and characteristic features of the invention will be in part apparent, and in part pointed out as the description progresses. i

Generally speaking, and without attempting to define the nature and scope of the invention, it is proposed to control a yard signal overfa pair of line wires in accordance with the number and polarity of pulses in a selecting code, using a manually operable switch to determine 'the'polarity, "and a conventional telephone dial switch to determine the number of impulses. Itis also proposed to provide a bank of stepping relays and associated control relays and circuits for .selectively overning the control or lighting circuits of the signal in acocrdance with the code transmitted, such' an organization of conventionalrelay structures being considered to be more suitable for railway use than step-by-step switches or like mechanical devices.

13 Claims. (Cl. 177-353) than to illustrate the detail construction and arrangement of parts preferably employed in praccontemplated.

In the interests of simplifying the illustration, I

various contacts of the relays and other parts have been illustrated diagrammatically, and the symbols and are conveniently employed to designate connections to the opposite terminals of a battery or other suitable source of operatin current.

" The signal or indicating means governed in accordance with this invention may take various forms, and the signal S indicated in Fig. 3 and similar to that disclosed for example in the patent to P. M. Gault, No, 1,875,587, September 6, 1932, is merely typical, This type of yard signal comprises a number of light projecting units designated 2, 16 being shown, each having a distinctivenumber or like insignia formed on its cover glass, or other part of the optical system, in such a way that when the associated electric lamp is lighted, the desired indication of a track number or the like is displayed. For example, these light units may be of a form disclosed by the patent to S. M. Day, No. 1,548,984, August 11, 1925. The signal as a whole is provided with a suitable visor or sunshade 3 to minimize objectionable phantom' indications by reflected external light.

, The purpose of the present invention is to provide facilities for selectively closing control or lighting circuits for the indicators by code transmission over a pair of line wires. One form of means in the yard oflice or similar control point for creating the desired code, illustrated in Fig.

1A, comprises a conventional telephone dial switch DS of the well known construction commonly used in telephone dial switching systems, and a three-position hand switch or key K. The telephone dial switch comprises the usual rotatable disc 5 with the usual finger holes, back of which are the fixed numbers. In the arrangement shown, provision is made for selectively controlling 16 different, indicating lamps; and since polarity as well as the number of pulses is employed for selection purposes, the dial switch has only 8 openings, each of which relate to two different signal codes such as 1-9, 2-10, 3-11 etc. A normally closed contact 6 intermittently opened by an operating cam I of the dial switch DS in the usual way is included in one of the line wires LI, so that when the dial switch is operated in the usual way to dial a givennumber, this line wire LI is intermittently openedthe same number of times.

The contacts 8, 9 shown conventionally and operated by the three-position key switch K govern the continuity and polarity of the connections from a battery B, or other suitable source of current to the line wires. LI; L2,; An

indicating lamp I2 connected across the resistance IS in the line wire L2 is preferably employed to indicate when current is circuit.

Referring to the field apparatus shown in Fig 1B, this comprises a three-position polar line relay F, biased to its intermediate position, a quick-acting repeater relay FP, positive and ne ative conditioning slow-acting relays PSA and NSA, a suitable light control relay LC, a bank of four stepping relays VI, V2, V3, V4, a repeat stepping relay VR, and a half-step relay VP.- All of these relays, except the polar line relay F, are of the conventional telephone type, commonly used in code communication systems for centralized trafllc control on railroads, these relays operatfiowing in the line 4 contact ill of relay FP, bus 32, through back contacts 33, 34, 35, 36 of relaysVd, V3, V2 and VI respectively, relay VP to This energization of the relay VP and closure of its front contact 38. establishes a stick circuit for this relay which may be traced from ,through frontcontact 30 of relay LC, front contac't38 of relay VP and through the back contacts 33 to 36 of relays V4 to VI, the same as in the pick-up circuit for this relay. Also, the closure of the front contact 39 of the relay VP prepares an auxiliary stick circuit for this relay including the back contact 3| of the line repeater relay .FP;

time the contact 6 in the line wire LI is opened -by the dialswitch DS for the first count of the ing quickly to open and close theircontacts'unless made slow-releasingby copper slugs; or the equivalent in accordance with the usual practice. A suitable source of current, assumed to be an alternating current source with terminals BX and CK is provided for lighting the indicating lamps of the signal when their respective control circuits are closed. I L

Typical operation.Referring; to the formof the invention shown in Figs. 1A and 1B, the parts J and circuits are illustrated in the normal condition under which no indication for the yard signal is displayed. The line wires LI, L2 are deenergized, and all of the relaysof thefield appa ratus are deenergiz ed. 3

Assuming that the yard master or other operator desires to instruct;the next train tonioye n; ya t ck-12 i ex m l he o e a key switch K to the upper position, since that position is for the group of numbers 1 to 8 including 2, and then dials the number 2 on the telephone dial switch. The operation of the key switch K and its contacts 8, 9 connects the battery il to the line wires Ll, L2 with one. polarity, conveniently considered to be This energizes line of relay PSA, bus I9, back contacts'2I, 22;, 23 and 24 of relays V4, V3, V2 and VI, respectively, 're' lay LC to This energiz ation of. relay- LC closes its front contact 26 tdconhectK-l-l to the polar contact finger I5 of .relayF, thereby energizing its repeater FP over an obviouscircuit.

This energizationof relay FP, with relay LC energized, establishes a pick-up circuit for .the half-step relay VP which may be. traced from through'front contact 30 ofrelay LC, front code under consideration, the line relay F and its repeater FP are deenergized; and this picks up the first: step relay VI over a circuit from through front contact 40 of .relayLC, back contact fi'l of relay FP,"fr'ont contact 42 of. relay VP, back contact 43 of relay V2, and lower winding of relay VI to The step relay VI is held up by. astick circuit .from the bus I9, connected to through front contact I8 of relay PSA, through back contact 46 of relayVZ and front contact 4'1. of relay VI, and itsupper winding to During this time the half-step relay VP is held up by its auxiliary stick circuit above mentioned.

The pick-up circuit for the light control relay LC is'broken at the back contact 24 of the step relay VI, but while the. line relay F is deenergized, this relay LC .is held up by a stick circuit which may be traced from through back contact 48 of v relay FP, front contact, 49 of relay- PSA, front con'tact'fifl of relay LC, and relay LC to The next time'the line circuit is energized and the relay FP- opens its back contact 48; the relay LC is deenergized; but this relay LC -is suificientlyslow-releasingto maintain its armature and contact fingers in the attracted position during the relatively short time the line circuit is energized between the successivepulses of the counting code. ,Wh'enJthe contacts Bof the dial switch close after this first count, the resultant energization of the line relay. F and its repeater F cause ashift or'd'eenergization'oi thev relay VP ready for the next step..' The relay VP is deenergize'd because its pick-up circuit and first stick. circuit above traced are broken with the back contact ,36. of steprelay VI now energized, and'its auxiliary stickj circuit through its" front contact 39 and back contact 3I of .relay'FP is broken by the energization of relayFP. g

The next opening of theline circuit by the operation of the c'ontacts 6 of the dial switch for the second count, and they resultant deenergiza- 'tlon of the relay Restablishes a pick-up circuit for, stepirelay V2 from through front contact of relay. LC, back contact 4.I of, relay FP, back'contact 42 of relay VP, back contact SI 'of relay V3, front contact.52 of relay VI, and lower winding of V2 to .This energization of relay V2. and 'opening of its back contact 46 breaks the stick'circuitpreviously traced through the upper winding of therelayVI, to release that relay.

Since relay V2 is being picked up through a circuitjincluding afron't. contact 5| of .the.relay VI, .an .fauxiliary ,1 stick circuit for each stepping relay, controlled by the contact 56 r of relay VP andafbackcontact oftherelay FP, is preferably employed to hold up the next preceding step relay when a step relay is energized, i. e.; hold up relay VI, while relay V2 is being energized, until such energization is completed and the line. circuit is again energized to shift the relay VP. This auxiliary stick circuit in the case of relay VI may be traced from through contact I8 ofv relay PSA, back contact 55 of relay FP, back contact 56 of relay VP, and front contact56 of relay VI through its upper winding to It can be seen that this auxiliar stick circuit for the step relay VI is closed, and the relay VI is held up during the period of energization of the relay V2, and is not released until the relay FP picks up during the next energization of the line circuit.

In the example of a 2 count assumed, after the second pulse and energization of the step relay V2, followed by the release of relay VI, further interruption of the line circuit ceases, and the line relay F remains steadily energizedwith the polarity assumed. Under these conditions, the light control relay LC releases after a time, its pick-up circuit being broken at back contact 23 of relay V2 now energized, and its stick circuit at the back contact 38 of relay FP. This deenergization of relay LC and opening of its front contact 26 in turn drops relay FP, The positive selecting relay PSA, however, is maintained energized through its pick-up circuit and the polar contact l6 of the relay F in its right-hand position.

Under these conditions, upon release of the light control relay LC, the primary 65 of the transformer T supplying current to the lighting circuits is energized from a suitable source of alternating current from BX, through front contact 6! of relay PSA, back contact 62 of relay LC, primary of transformer 66, to CX. With the relay PSA energized and the repeat relay VB deenergized, the indicator 2 is included in the secondary circuit of the transformer by connections which may be traced from the upper terminal of said secondary 64, wire 65, back contact 66 of relay VR, front contact 6? of stepping relay V2 now energized, lamp 2, wire 63, front contact 69 of relay PSA to the upper terminal of said secondary.

Thus, at the termination of the polar count code in question, the corresponding indicator lamp 2 is lighted; and this condition continues until the operator shifts the key switch K to the middle position to deenergize the line circuit and release line relay F, whereupon the positive selecting relay PSA is deenergized, and the stepping relay V2 then energized is restored to its normal condition.

Similar circuits are involved in the operation of selecting signals for other counts of '1, 3, and 4 of the same polarity. If the key switch K is shifted down to the other position to energize the line circuit with the other or negative polarity, the negative selecting relay NSA is energized through the polar contact l2 of relay PSA. This negative selective relay NSA closes front contacts 73, i l and 75 in multiple with the front contacts I8, 49, iii respectively of the relay PSA, so that the same stepping operations and energization of the transformer T occur with relay NSA energized, as previously described for relay PSA energized. The energization of the negative selecting relay NYS A and the closure of its front contact ll, however, connects different lamps to the secondary 54 of the transformer T for thesame step relay then energized. For example, if the negative selecting relay NSAis energized with the -ment.

,steprelay V2 energized, the indication lamp I0 is lighted instead of indicating lamp 2, over a circuit which may be traced from wire 65, through back contact I8 of repeat relay VR, front contact I9 of relay V2, lamp In, wire 80, and front contact 11 of relay NSA.

- Thus, the polarity of the pulses, as well as the umber of pulses, determines the selection and provides for the control ofv twice as many indicators-as could be governed in accordance with the .number of pulses of a fixed polarity.

In; the arrangement shown, provision is also made for-operating the same step relays VI to V4 for, asecond time to absorb counts 5, 6, '7 or 8. Briefly-considering this repeat operation, during the energization of the line after the fourth stepping pulse, the relay VP is energized through front ;contact 33 of relay V4 then energized, and the pick-up circuit for the step relay VI is prepared,

S0 that this relay VI is energized for the second time on the 5th code pulse. This second energization ofthis relay VI, with relay V4 also energized, closes a pick-up circuit for the repeat relay VR from,-(+), through front contact 83 of relay 'VI, front contact 84 of relay V4, and lower winding of relay VR. Relay VB is held up by a stick cire cuit readily traced through its front contact 85 to the bus I9- connected to throughfront contacts l8 or l3 of relaysPSA or NSA.

Thus-when the stepping relays VI to V4 are operated for the second time, corresponding with code counts 5, 6', 7 and 8, the repeat relay VB. is

energized, thereby shifting its contact fingers 66 and 18 to provide for the energization of a different group of indicating lamps for the same polarity and step relay energization. Forexample, if the step relay V2 is energized for a count of .6, the lighting circuit for lamp 6 is established through front contact 66. of relay VR, if thel positive selectin relay PSA is energized, 'while the lighting circuit for lamp I4 is completed through front contact I8 of relay VR if "thenegative' selecting relay NSAis energized.

The organization of this invention avoids un-' desirable and improperoperations by careless or accidental manipulation of the sending equip- After a selectingv code has been transmitted and the light control relay LC has released to energize the particular lighting circuit selected, the energizin circuits for the. stepping. relays are broken at the front contact 40 of. this relay LC, so that any careless or idle movement of the telephone dial switch and intermittent interruption of the line circuit will not operate any additional stepping relays, orchange the existing selection. In order to extinguish :any indicatin lamp or change to a different indication, the line circuit has to be opened long enough to release either the relay P-SA or the relay NSA that may happen to be energized,

thereby opening front contact I8 or 13 to break the stick circuit for the step relay then energized, and complete the pick-up circuit for the 2,424;eco

scribed, a movement of the key switch S and a change in the polarity of energization of the line circuit will not change to the indicating-lamp having its circuit controlled by the relay NSA, since this relay NSA cannot pick up untilrelay PSA has released. K

Each of the relays PSA and NSA is-also provided with a stick circuit to maintain it enersized if the contact finger l6 of the polar line relay F moves from one extreme position to the other, without remaining in the middle position long enough for the'relay PSA or NSA then energized to release, these relays being slightly slow releasing 'to maintain their armatures and contacts in the attracted position during the relatively short times that the line circuit is deenergized" during normal code transmission; This stick circuit for the relay PSA may be traced from contact finger 16 of line relay E to the left, front contact 12 of relay PSA, and winding of this relay to Consequently, a relatively quick movement of the key switch K from one extreme position to the other for any reason, and the resultant change in polarity of energization of the line circuit, will not shift to a different signal indication, nor change'the then existing signal indication.

It will also be noted that the control or lighting circuits are not energized until the relay LC releasest'at the end of the counting-code being sent." Consequently; there is no flashing f of the lampsas the steppin'grelays are being-operated to prepare the final'selection circuits. i

' Modification-x-Fig. 2 illustrates a 'mo'dified formiof the code 'sendingior coding equipment designed to simplifylthe.manipulation, minimize the; chanceiforerror, and indicate to the operator. 'what' particular signal is V beinglrdisplayed. In I this ,modification, alnumber of. openings 'for contact :receptacles, similar. to the conventional telephone jack and designated 90, V are arranged around the dial switch; with two such openings OppOs'iteLeach finger hole of the dial.v Thelnum- -bers' identiiyingthe difierent signal. indications 'are associated. with these contact receptacles, rather than ithefingerr holes, on the telephone dial A-snitalolei'pluglor contact :pinYSl, constitutin iiin effect a token, may be conveniently connected to the" panel by a suitable chain 92 'or lthe. likeiand used, ;to close spring contacts 93 shown iconventionally, when inserted one of the openings-ofthese contact receptacles.-. .The co'ntactsili3 of the inner series ,of'receptacles are COnh eCtdtOfa. relay'PC and those for the. outer series .to.another' relay NC; and. theserelays .PC :andgNCioperate,contacts 96,91, 98, 99tojconne'ct thetbattery B to the ,line wires LI and. L2 with positivelandmeg'ative polarity byreason of the obvious circuit. connections shown. 7 V .In this modified arrangement when the opererator desires to display a particular indicator, he inserts the token 9| into the-opening bearing a corresponding-number, thereby closing the associated ,contacts 93 to energize ,eitherthe relay PC or the relay NC, as the case-maybe, to determine thev polarity of the code Pulses reouired to s'electthis particular indicator; The operator then puts his finger in the hole inthe telephone dialopposite the location of the token, piillslthe-dial against the stop, and lets go. 'This transmits a ppropriate 'nmnber of pulses of 'the proper'polarityi f" -1 The useof the token 9| in-the-va1 iou's receptaclesj in this ma ner not only facilitates the selection of the polarity desired for the selectionabeing made, but also affords a visual indication identifying the particular indicator for whichthe code was last transmitted. In other words, the operator can tell from the location of-thetcken Blwhat track indication is being displayed on the yard signal, assuming of course that after the token'was positioned the telephone diarwas operated, and the field equipment properly responded. v

Whenthe display of a track indication is no longer needed, the token 9| may be removed,

be made toadapt the invention to the particular problem encountered in practicing the same without departing from the spirit or scope of the invention, :except as demanded by the scope of the following claims. .Whatlclaim as new is:

1. In a system for the remote selective control of. the indicators of a multiple aspect railway signal over a pair of line wires extending from a control point to the field location of said signal, a telephone dial switch at the control point for applying a selected number of pulses to said line wires, manually operable pole-changing contacts at the control point for governing the polarity of such pulses, and apparatus at the field location responsive to the number and polarity of code pulses comprising, a plurality of circuits for governing the indicators of said signal, means responsive to the polarity of the code pulses for selecting between two groups of said circuits, a bank of stepping relays energized one at a time in response to the successive deenergizations of said line circuit for selecting between the individual circuits of the selected group in accordance with the number of the'pulses, and means whereby a sudden change in-p'olarity of energization of said line Wires will not change the indicating aspect of said signal.

"2. In a system for the remote selective control of difierent indications of a multiple aspect railway signal, a pair of line wires extending from a control point to the field location of said signal, means atthe control point including manually operable pole-changing contacts and a telephone dial switch for energizing said line wires with a selected number of current pulses of one selected polarity, a plurality of control circuits for separately governing the indications of said signal, means including a bank of stepping relays responsive to the polarity and number of pulses applied to said line wires for selecting one of said lighting circuits, means responsive to a sustained energization of said line wires for energizing the particular control circuit selected, and means for preventing pole-changing oi the energy on said line wires after the first of a series of impulses changing the indicating aspect of said signal.

3. Ina system for remotely controlling the various indications of a multiple aspect railway signal 'over a line-circuit extending from a distant control point, means at the control point inc1ud ing a telephone dial switch for applying impulses of a selected number and polarity to said line cir..

cult and for thereafter maintaining said line circuit energized until manually restored to normal, a plurality of control circuits for the indications of said signal, means at said signal including a selected control circuit so long as said line cir-' cult is thereafter maintained energized, and means for preventing a change of polarity of the impulses after the first impulse producing any eifect upon the indication to be displayed.

4. In a system of the character'described for governing the indications of a multiple aspect railway signal over a pair of line wires from a distant control point, a plurality of control circuits for governing the indications of said signal, conditioning relays selectively energized in accordance with the polarity of initial energization of said line circuit for selecting between two groups of said control circuits, a bank of stepping relays energized one at a time response to the successive pulses applied to said line circuit regardless of their polarity for selecting individual control circuits of the selected group, and means responsive to a sustained energization of said line circuit following the transmission of the code pulses of the selected polarity and number for energizing the control circuit selected so long as said line circuit is energized.

5. In a system of the character described for the remote selective control of the different indications of a railway signal, a line circuit extending from a control point to the location of 'said signal, a polar line relay connected to said line circuit, two conditioning relays respectively energized in response to the energization of said line relay with a, corresponding polarity only if the other conditioning relay is then deenergized, a bank of stepping relays energized one at a time in response to the successive operations of said line relay regardless of polarity, and a plurality of control circuits for the indications of said signal selectively closed by contacts of said conditioning relay and said stepping relays.

6. In a system of the character described for the remote selective control of indications at a railway signal over a line circuit from a distant control point, means for rendering effective a particular indication of said signal in response to the sustained energization of said line circuit following transmission of code pulses of a selected number and polarity, code sending means at the control point for applying code pulses to said line circuit including a telephone dial switch for intermittently opening said line circuit a predetermined number of times in conformity with the finger hole of the dial used, relay means operable to energize said line circuit with a selected polarity, and means set manually to different selected positions for designating the finger hole of the dial to be used and for also selectively operating said relay means.

'7. In a system of the character described for governing the indications of a multiple aspect railway signal in accordance with the number and polarity of pulses transmitted over a line circuit from a distant control point, code sending means at the control point for intermittently energizing said line circuit in accordance with a selected code comprising, a panel containing a plurality of pairs of holes, a telephone dial switch associated with said panel and including a finger hole" for each of said pairs of holes and for intermittently opening said line circuit the particular number of timescorresponding with the finger hole in the dial used, means including a token movable to a particular pair of holes for identifying the finger hole of the telephone dial switch to be used and to a particular hole of such pair for selectively determining the polarity of energization of said line circuit, whereby the location of said token after each operation shows which indication of the signal was last selected, and multiple aspect railway signal means controlled over said line circuit by said code sending means.

8. In a system of the character described for selectively controlling the indications of a multiple aspect railway signal in accordance with the polarity and number of pulses transmitted over a line circuit from a distant control point, the combination with apparatus adjacent the signal including a bank of stepping'relays for rendering eifective a particular indication of said signal in accordance with the number and polarity of the impulses last transmitted over the line circuit, of manually operable means governing the impulses applied to said line circuit and comprising, a telephone dial switch, a plurality of token receptacles relating to the different indications of said signal and arranged in two rows around the rotary dial of said telephone dial switch and opposite the finger holes in said dial, and means governedby the insertion of a token in any receptacle of each of the different rows for determining the polarity of the pulses applied to the line circuit by operation of said telephone dial switch, whereby the location of the token is indicative of both the number and polarity of the impulses transmitted,

9. In a system for the remote selective control of a number of signal indicators over a pair of line wires from a distant control point, manually operable means for applying a selected number of pulses to said line wires of a selected polarity, a repeater line relay at the field location responsive to the energization of said line wires regardless of polarity, a plurality of control circuits for said signal indicators, means responsive to the polarity of the first impulse only of energization of said line wires for selecting between two groups of said control circuits, a bank of stepping relays energized one at a time for selecting between the individual control circuits of the selected group in accordance with the number of impulses transmitted, and means including a slow-release control relay for causing energization of the selected control circuit in response to a sustained energization of said line circuit following transmission of a series of selecting impulses.

10. In a system of the character described for selectively governing the indications of a multiple aspect railway signal from a remote control point over a pair of line wires, two sets of control circuits for governing the difierent indications of the signal, means including a bank of stepping relays energized successively in response to the intermittent energization of the line wires for selecting between control circuits of each of said two sets, means responsive to the polarity of the first energization only of said line circuit for selecting a particular one of said sets of control circuits, relay means actuated by a sustained energization of the line circuit after transmission of a selectingic'ode forenergizing theiparticularsignal control circuit-selected, and means for pre-' venting operation oi said stepping relays while said relay means is actuated.

11. A system for selectively governing the indicationsof a multiple aspect railway signalirom'.

a remote control point over a'line circuit comprising, manually operable means at the control point for energizing said line circuit with a variable selected number of time spaced pulses, means including a bank of stepping relays for selectively governing the indications of the signal inaccordance with the number of pulses in the selecting code transmitted, and means responsive itoasusrality of control circuitsfor the different ind-ica tions of said signaLa bank of stepping relays for in part selectively governing said control circuits in accordancewiththe number of impulses applied to said line wires, a polar line relay for governing the operation ofsaid stepping relays, two conditioning relays one for each possible polarity of energization of said line Wires, a pick-up circuit for'initially energizing that one of said conditioning relays-during the first impulse ofa series of impulses which corresponds in polarity to that impulse, and a stick circuit for each of said conditioning relays for holding the energized conditioning relay energized when the energize.- tion of said line relay is changed to the other 12 polarity, and'means for controlling said control circuits by said stepping relays and said conditioning relays.

13. In a signal system of the character described for governing the indication of a multiple aspect signal from a remote point over a pair of line wires, two sets of control circuits associated with saidsignal, polarity responsive means responsive to the polarity of the first of a series of impulses transmitted over said line wires, steppingrelays for counting the number of impulses of such series, means for selecting a particular set of said control circuits depending on the condition of said polarity responsive means, means including said stepping relays for selecting a particular control circuit of the selected set, means responsive to the termination of said series of impulses for energizing the selected control circuit of the selected set, and means for transmitting a series of impulses over said line wires of a "number and with the first impulse of a polarity aspect to be displayed THOlVIAS J. JUDGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS depending on the final 

